Wide beam reconstruction “quarter-time” gated myocardial perfusion SPECT functional imaging: a comparison to “full-time” ordered subset expectation maximum

doi:10.1007/s12350-009-9108-7

Journal of Nuclear Cardiology

Volume 16, Issue 5, October 2009, Pages 736-752

https://doi.org/10.1007/s12350-009-9108-7 Get rights and content

Abstract

Background

Previously we reported that compared to iterative reconstruction with ordered subset expectation maximum (OSEM), wide beam reconstruction (WBR), which incorporates resolution recovery and controls noise during reconstruction without applying a post-processing filter, allows half-time SPECT acquisition with preserved diagnostic quality. We now postulate that with further Poisson noise treatment, quarter-time acquisition is possible.

Methods

The half-time WBR algorithm was optimized for quarter-time acquisition based upon anthropomorphic cardiac phantom data and a pilot group of 48 patients (pts). Then using the modified algorithm, 209 pts (91 men, 118 women, mean chest circumference = 40 in) were imaged at rest (R) and stress (S) (9/32 mCi ^99mTc-sestamibi) full-time with OSEM, and again quarter-time with the modified WBR algorithm. The 180°, 64-stop, full-time single-day rest (R) (25 second-per-stop, sps) and 8-frame per cardiac cycle post-stress (S) (20 sps) gated SPECT, and then quarter-time R (6 sps) and post-S (4 sps) gated SPECT were acquired. Blinded observers graded scan quality (1 = poor to 5 = excellent) based on myocardial uniformity, endocardial/epicardial edge definition, and background noise. Perfusion defects were scored using a 17-segment model. Using three commercially available software methods, end-diastolic volume (EDV), end-systolic volume (ESV), and left ventricular ejection fraction (LVEF) were calculated.

Results

For the 209 prospective pts, mean image quality for R full-time OSEM and quarter-time WBR were similar (3.5 ± 0.9 vs 3.6 ± 0.7, p NS). For S, quarter-time WBR quality was superior to full-time OSEM (4.3 ± 0.7 vs 3.9 ± 0.7) (P = 1.78 × 10⁻¹⁷). In 35 pts with chest circumferences >44 inches a longer, 10 sps WBR acquisition improved resting image quality. Of 48 pts with abnormal scans (SSSs > 2 by OSEM) mean summed stress scores, summed rest scores, and summed difference scores were not significantly different with quarter-time WBR vs full-time OSEM (11.2 vs 10.9), (9.1 vs 9.0), (2.0 vs 1.9) (P NS). For the three software methods, there was a good correlation of LVEF, EDV, and ESV determined by WBR vs OSEM (all r > 0.92). ESVs were generally higher with WBR, primarily due to better delineation of the valve plane at end-systole, whereas EDVs were similar. Thus, EFs were significantly lower with WBR.

Conclusions

For perfusion SPECT quarter-time WBR affords image quality, defect characterization, and functional assessment equivalent to full-time OSEM.

Introduction

Recently, considerable effort has been put forth to decrease the scan time and radiation dose associated with myocardial perfusion SPECT. New higher speed cameras have been developed with solid state based detector technology that demonstrates the potential of considerably shortening acquisition time.¹ All major scintillation camera vendors have released a software packages with the capability of processing lower count density data obtained with shorter acquisition times.2, 3, 4, 5

Wide beam reconstruction (WBR) is an iterative reconstruction method which simultaneously addresses resolution recovery and noise reduction for low count density data. We and other investigators have reported that compared to filtered back projection (FBP), WBR, which models noise in the reconstruction process, maintains or even improves myocardial perfusion SPECT quality, even with lower count density “half-time” acquisitions.6, 7, 8, 9, 10, 11, 12 Because the WBR algorithm has the potential to cope with even lower count density data with higher noise content, we postulated that this new software method could be further modified to provide diagnostic quality gated myocardial perfusion SPECT with even shorter, “quarter-time” stress and rest acquisitions.¹³^,¹⁴ Based on phantom studies and pilot patient results, the WBR approach was optimized to address quarter-time statistics. The new method was then validated in 209 study patients.

Section snippets

WBR Processing for “Quarter Time” Data

Wide beam reconstruction (UltraSPECT, Ltd., Haifa, Israel) accurately models the physics and geometry of the emission and detection processes. This method has been described in detail in previous publications.⁶ Specifically, WBR calculates the probability relations between reconstruction voxels and projection pixels based on information regarding the collimator used. This three-dimensional collimator distance response is calculated analytically for each voxel by taking into account the solid

Image quality

Despite “quarter-time” acquisitions, compared to “full-time” OSEM, stress perfusion image quality [1 (poor) to 5 (excellent)] increased significantly with “quarter-time” WBR (4.3 ± 0.7 vs 3.9 ± 0.7, P < 0.00001). In general, myocardial count density and uniformity, endocardial and epicardial edge definition, and visualization and definition of the right ventricle were superior with “quarter-time” WBR, and background noise was less.

However, in the entire patient study population there was no

Discussion

Previous studies comparing “full-time” FBP with “half-time” WBR scans ⁶^,⁷ have reported equivalent or improved image quality with “half-time” WBR.

In the present study, we have demonstrated that compared to OSEM processing of “full-time” SPECT gated myocardial perfusion acquisitions, WBR preserves or even improves the image quality of “quarter-time” SPECT acquisitions performed with a high-resolution parallel-hole collimator. In a subset of 35 patients with chest circumferences >44 inches,

Conclusions

For perfusion SPECT “quarter-time” WBR affords image quality, defect characterization, and functional assessment equivalent to full-time OSEM, providing the potential for decreased SPECT acquisition times and/or decreased radiopharmaceutical doses.

Acknowledgments

Grant support: UltraSPECT, Ltd., Haifa, Israel.

References (17)

SharirT et al.
High-speed myocardial perfusion imaging: Initial clinical comparison with conventional dual detector anger camera imaging
J Am Coll Cardiol Img
(2008)
CullomSJ et al.
An optimized iterative reconstruction and processing protocol for “half-time” (32 projections) REST/STRESS Tc99m-sestamibi myocardial perfusion SPECT
J Nucl Cardiol
(2008)
Borges-NetoS et al.
Clinical results of a novel wide beam reconstruction method for shortening scan time of cardiac SPECT perfusion studies
J Nucl Cardiol
(2007)
CantinhoG et al.
WBR versus FBP in myocardial perfusion SPECT reconstruction-diagnosis impact
J Nucl Cardiol
(2007)
CantinhoG et al.
Wide beam reconstruction technology: Does it respect myocardial perfusion SPECT functional parameters?
J Nucl Cardiol
(2007)
BatemanTM et al.
Multicenter investigation comparing a highly efficient half-time stress-only attenuation correction approach against standard rest-stress Tc-99m SPECT imaging
J Nucl Cardiol
(2008)
PattonJA et al.
Recent technologic advances in nuclear cardiology (image reconstruction advances)
J Nucl Cardiol
(2007)
Maddahi J, Mendez R, Babla H, Bai Chuanyong B, Arram S, Conwell R. Prospective multicenter clinical evaluation of rapid...

There are more references available in the full text version of this article.

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Original ArticleWide beam reconstruction “quarter-time” gated myocardial perfusion SPECT functional imaging: a comparison to “full-time” ordered subset expectation maximum

Abstract

Background

Methods

Results

Conclusions

Introduction

Section snippets

WBR Processing for “Quarter Time” Data

Image quality

Discussion

Conclusions

Acknowledgments

J Am Coll Cardiol Img

J Nucl Cardiol

J Nucl Cardiol

J Nucl Cardiol

J Nucl Cardiol

J Nucl Cardiol

Recent technologic advances in nuclear cardiology (image reconstruction advances)

J Nucl Cardiol

Original Article
Wide beam reconstruction “quarter-time” gated myocardial perfusion SPECT functional imaging: a comparison to “full-time” ordered subset expectation maximum